A science experiment gone wrong forced Knoxville firefighters to evacuate a building on UT's campus for two hours Tuesday due to a toxic gas.

Around 3:45 p.m., Knoxville Fire Department said they received an emergency call at the Science and Engineering Research Facility on Circle Drive.

KFD spokesperson, DJ Corcoran, said students were experimenting with the gas boron trichloride.

According to the National Oceanic and Atmospheric Administration's website, "Boron trichoride is a colorless gas with a pungent odor. Fumes irritate the eyes and mucous membranes. Corrosive to metals and tissue and is toxic. Under prolonged exposure to fire or intense heat, the containers may rupture violently and rocket. Used as a catalyst in chemical manufacture, in soldering fluxes, and for many other uses."

KFD said when the students heated up a small amount of the gas, the glass container holding it broke and caused it to leak into the lab. Corcoran said the heat burned up most of the gas but transformed it into hydrogen chloride which also created danger.

Corcoran said one student ran back inside to make sure the gas was turned off, helping to keep the situation under control.

No one was injured, but KFD sent the four students involved to UT Medical Center as a precaution. Fifty people in other parts of the building were evacuated for about two hours.

KFD's Hazardous Materials Unit used fans to ventilate the lab and tested the PH levels to make sure the lab was safe before reopening the building.

The unit is trained to deal with dangerous chemicals like boron trochloride because of two major Interstate cross hairs, I-75 and I-40, that brings cargo through Knoxville.

"There's a lot of chemicals that come through Knoxville everyday. So these guys that are qualified that are on this unit they have to know how to respond to any type of wreck or exposures," said Corcoran.